Wireless intelligent switch engine

ABSTRACT

A wireless intelligent switch engine (WISE) is described. The wireless intelligent switch engine provides for automatic switching between different physical wireless interfaces in mobile devices while roaming to maintain a wireless network connection. WISE functions as a bridge between a mobile device and multiple wireless network interfaces to provide automatic and seamless switching among networks while roaming. The mobile device sees WISE as a LAN interface and communicates with WISE using the TCP/IP protocol stack, thus providing a PPP-less configuration that uses the TCP/IP protocol stack regardless of the wireless interface.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority from U.S. provisionalapplication serial No. 60/429,480 filed on Nov. 26, 2002, incorporatedherein by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0002] Not Applicable

INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC

[0003] Not Applicable

NOTICE OF MATERIAL SUBJECT TO COPYRIGHT PROTECTION

[0004] A portion of the material in this patent document is subject tocopyright protection under the copyright laws of the United States andof other countries. The owner of the copyright rights has no objectionto the facsimile reproduction by anyone of the patent document or thepatent disclosure, as it appears in the United States Patent andTrademark Office publicly available file or records, but otherwisereserves all copyright rights whatsoever. The copyright owner does nothereby waive any of its rights to have this patent document maintainedin secrecy, including without limitation its rights pursuant to 37C.F.R. §1.14.

BACKGROUND OF THE INVENTION

[0005] 1. Field of the Invention

[0006] This invention pertains generally to wireless networking, andmore particularly to an apparatus and method that provides for automaticswitching between different network interfaces in a mobile device sothat the mobile device can seamlessly roam among different types ofwireless networks.

[0007] 2. Description of Related Art

[0008] In recent years, wireless network interfaces have becomeextremely important to the functionality of mobile devices. Examples ofmobile devices that use wireless networking are laptop computers andpersonal digital assistants (PDAs). Wireless connectivity of a mobiledevice to the Internet or to an intranet can increase mobility,convenience and productivity, but there are certain limitationsassociated with that connectivity. For example, the widely used IEEE802.11 (WLAN) wireless networking technology provides high bandwidth butis limited in geographical coverage. On the other hand, while cellulartechnologies such as CDMA/WDCMA/GSM/GPRS (WAN) provide much wider (andeven global) geographical coverage, they do so at a much lower bandwidththan 802.11 networking.

[0009] Due to the use of different standards and communicationsprotocols for wireless networking, in order to achieve true globalcoverage it is currently necessary to utilize a combination of severalplug-in or integrated connectivity interfaces and to manually switchbetween interfaces while roaming through different geographical areas orcommunication sites. For example, a laptop computer or PDA may have anintegrated 802.11b interface and one or more PCMCIA or CF-card slots forswappable add-on cards. This allows the user to, for example, selectamong IEEE 802.11a, IEEE 802.11b, CDMA/WCDMA or GSM/GPRS wirelessinterface cards. Again, however, the user experiences a degree ofinconvenience since it is necessary to manually enable, disable orotherwise switch between the interfaces. For example, the user may haveto manually switch from an 802.11 module to a CDMA/WCDMA or GSM/GPRSmodule if the user moves from 802.11 hot spots to cellular networks.With many operating systems, this also requires the user to close thenetwork connection session and restart it again using the new wirelessinterface.

[0010] Those skilled in the art will appreciate that networkcommunications typically rely on the Open Systems Interconnection (OSI)Reference Model in which there are seven communications layers.Currently, products are available that use OSI Layer 5 to provideproxy-based session level mobility and OSI Layer 3 with Mobile IP toprovide network level mobility. However, those products are based on aclient/server architecture and roaming connection changes requireinteractions of both client and server components.

[0011] Accordingly, there is a need for seamless roaming capability tobe built-in to mobile devices so that different wireless interfaces willautomatically be selected while roaming without the need for manualselection and/or restarting the wireless networking session. The presentinvention satisfies that need as will herein be described.

BRIEF SUMMARY OF THE INVENTION

[0012] The present invention provides for the automatic switchingbetween different physical wireless interfaces in mobile devices whileroaming to maintain a wireless network connection. In general terms, theinvention comprises a wireless intelligent switch engine (WISE) thatfunctions as a bridge to provide network connection switching betweendifferent interfaces.

[0013] According to an aspect of the invention, network connectionswitching is accomplished through the use of Open SystemsInterconnection (OSI) Layer 2 Media Access Control (MAC) bridgingtechnology. Those skilled in the art will appreciate that OSI specifiesseven layers ranging from the physical layer to the application layer.Layer 2, the data link layer, defines rules for sending/receiving dataacross the physical connection between two systems.

[0014] In one embodiment, the present invention comprises a Layer 2bridge that provides network switching between WLAN (802.11) or WAN(GSM/GPRS/CDMA/WCDMA) using 802.1p/802.1D/802.11 standards to select thedesired wireless interface. In one embodiment, the bridge resides withinthe mobile device. In another embodiment, the bridge is external to themobile device.

[0015] As can be seen, therefore, an object of the invention is to allowa mobile device to connect to any wireless network seamlessly. Furtherobjects and aspects of the invention will be brought out in thefollowing portions of the specification, wherein the detaileddescription is for the purpose of fully disclosing preferred embodimentsof the invention without placing limitations thereon.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

[0016] The invention will be more fully understood by reference to thefollowing drawings which are for illustrative purposes only:

[0017]FIG. 1 is schematic diagram of a wireless network connected towhich a mobile device is connected using a wireless intelligent switchengine according to the present invention.

[0018]FIG. 2 is diagram showing the relationship of the protocol stacksin a mobile device and a wireless intelligent switch engine according tothe present invention.

[0019]FIG. 3 is a diagram showing an embodiment of the protocol stacksused in a wireless intelligent switch engine according to the presentinvention.

[0020]FIG. 4 is a diagram showing the Open Systems Interconnection (OSI)Reference Model with Layer 2 Media Access Control (MAC) used in thepresent invention.

[0021]FIG. 5 is a block diagram showing the internal architecture of thewireless intelligent switch engine of the present invention.

[0022]FIG. 6 is a block diagram showing the IEEE 802.1 D protocol stackemployed in the present invention.

[0023]FIG. 7 is a block diagram showing the IEEE 802.1 D internalorganization of the MAC sublayer employed in the present invention.

[0024]FIG. 8 is a block diagram showing the internal organization of therelay block of FIG. 7.

[0025]FIG. 9 is a diagram showing the OSI Layer 2 packet header withIEEE 802.1p tag control employed in the present invention.

[0026]FIG. 10 is a block diagram of a dual mode 802.11a/b configurationsupported by the wireless intelligent switch engine of the presentinvention.

[0027]FIG. 11 is a block diagram of a WLAN and WAN configurationsupported by the wireless intelligent switch engine of the presentinvention.

[0028]FIG. 12 is a block diagram of a dual WLAN and WAN configurationsupported by the wireless intelligent switch engine of the presentinvention.

[0029]FIG. 13 is a block diagram of a WLAN and dual WLAN configurationsupported by the wireless intelligent switch engine of the presentinvention.

[0030]FIG. 14 is a schematic diagram illustrating the wirelessintelligent switch engine of the present invention functioning as agateway router between a mobile device and wireless network according tothe present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0031] Referring more specifically to the drawings, for illustrativepurposes the present invention is embodied in the apparatus generallyshown in FIG. 1 through FIG. 14. It will be appreciated that theapparatus may vary as to configuration and as to details of thecomponents, and that the method may vary as to the specific steps andsequence, without departing from the basic concepts as disclosed herein.

[0032] Referring first to FIG. 1, an example of a wireless network 10 isshown comprising a WAN 12 established by cellular carriers and a WLAN 14established by a high speed infrastructure, both of which are connectedeither wirelessly or by wired connections to the Internet 16. A mobiledevice 18, such as a laptop personal computer (PC) or personal digitalassistant (PDA), is also shown with capability of communicating withboth types of wireless networks. For seamless roaming between thosenetworks, mobile device 18 includes a wireless intelligent switch engine(WISE) according to the present invention as will now be described.

[0033] Preferably, the WISE is completely internal to the mobile device,but it will be appreciated that an the WISE can be implementedexternally as well. WISE communicates with the mobile device and thewireless interface devices, functioning as a bridge between the mobiledevice and the wireless interface devices such that, as the mobiledevice roams among the wireless networks, WISE automatically selects thewireless interface associated with the wireless network for seamlessroaming. This is accomplished, in part, by interfacing with the mobiledevice's TCP/IP protocol stack.

[0034] Referring to FIG. 2 and FIG. 3, an example of the relationshipbetween the protocol stack of the mobile device and that of the WISE canbe seen. As shown, the WISE 20 appears to mobile device 18 as a networkinterface card (NIC) 22, thus providing a PPP-less interface with themobile device's TCP/IP protocol stack 24, and bridging mobile device 18to the required wireless interface device such as WLAN interface device26 and WAN interface device 28 shown. By functioning as a bridge betweenthe mobile device and its associated wireless network interface devices,WISE 20 allows for seamless roaming among different wireless networks.

[0035] The invention automatically switches between the wireless networkinterface devices using bridging technology that is based on the OpenSystems Interconnection (OSI) Reference Model. As shown in FIG. 4, OSIspecifies a physical layer 30 (Layer 1), a data link layer 32 (Layer 2),a network layer 34 (Layer 3), a transport layer 36 (Layer 4), a sessionlayer 38 (Layer 5), a presentation layer 40 (Layer 6) and an applicationlayer 42 (Layer 7). The bridging technology employed by the WISE of thepresent invention is based on OSI Layer 2 Media Access Control (MAC) andthe IEEE 802.1 D bridging standard.

[0036] Referring now to FIG. 5, an embodiment of the WISE internalarchitecture can be seen. In the embodiment shown, WISE 20 comprises aQoS Priority Queuing module 50 (802.1p), a VLAN Bandwidth Tagging module52 (802.1Q), a Bridge Switching module 54 (802.1 D), a Switching/PacketManagement Table 56, and a buffering module 58 to provide dynamicfiltering and switching between a plurality of wireless interfaces.Referring more particularly to FIG. 6, the IEEE 802.1 D MAC Bridgespecifies an architecture and protocol for the interconnection ofnetworks below the MAC service boundary. The protocol stack 60 comprises802.2 Logical Link Control (LLC) 62 and 802.1 D bridging 64 forcommunication with, for example, 802.3 (Ethernet) MAC 66 and 802.11(WLAN) MAC 68 at the OSI data link layer 32 (Layer 2).

[0037]FIG. 7 and FIG. 8 illustrate an example of the internalorganization of the MAC sublayer based on 802.1 D. In FIG. 7, a firstnetwork 70 with LLC 72 and MAC 74 is shown interconnected to a secondnetwork 76 with LLC 78 and MAC 80 by means of an 802.1 D relay module 82and corresponding bridging MAC 84, 86 for each network interconnection.The 802.1 D bridging standard defines rules to provide relaycapabilities between the two networks. As illustrated in FIG. 8, relaymodule 82 comprises three components: a forwarding process 88, afiltering database 90, and a learning process 92. The forwarding process88 forwards received frames of data that to be relayed to other bridgeports. The forwarding process also filters frames on the basis ofinformation contained in the filter database 90 (e.g., QoS/priorityvalues) and on the basis of the state of the bridge ports (e.g., on/offbased on signal strength and availability of service). The learningprocess 92 observes the QoS/priority properties of frames received oneach port and updates the filter database 90 conditionally on the portstate. The filter database 90 holds filtering information and supportsqueries by the forwarding process 88 as to whether frames with givenvalues of the destination MAC address filed to be forwarded (relayed) toa given port.

[0038] WISE 20 then uses the priority field as defined in IEEE 802.1p toselect the proper wireless interface. WISE 20 assigns priorities (0˜7)based on frame quality; that is, based on the frame error rate (FER).The FER can be obtained from the wireless interface itself in most casesor can be computed from the receive frame CRC error. The prioritiesassignment can also use signal strength obtained from the wirelessinterface in addition to FER and CRC. Based on this information, thenetwork interface with higher priority or higher quality and higherbandwidth is selected as the preferred wireless connection.

[0039]FIG. 9 illustrates the packet header 100 used by WISE 20, which isan Ethernet OSI Layer 2 packet header with an 802.1p tag controlinformation field 102. The priority value maps to the 3-bits field 104of the packet header and the tag control information field 104 maps tothe switching/packet management table 56 (see FIG. 5) as one of theswitching criteria for the filter database 90.

[0040] To enable WISE 20 to select among a plurality of wirelessinterfaces, channel identifications are assigned to each of the wirelessinterfaces based on the IEEE 802.1Q standard. The VLAN identifier 106shown as part of the tag control information field 104 in FIG. 9 isdefined in the IEEE 802.1Q standard. WISE 20 uses this field to assignnetwork identification or channel numbers for LAN (interface with themobile host device), for WLAN, for CDMA/WCDMA or for GSM/GPRS networksso that WISE 20 can forward data packets to the appropriate channel andcorresponding network interface.

[0041] Referring now to FIG. 10 through FIG. 13, WISE 20 can beconfigured to support various combinations of wireless interfaces asshown. FIG. 10 shows a dual mode 802.11a/b configuration, FIG. 11 showsa WLAN and WAN configuration, FIG. 12 shows a dual WLAN and WANconfiguration, and FIG. 13 shows a WLAN and dual WAN configuration. Forexample, in FIG. 10, WISE 20 has one internal interface 200 (a LAN hostinterface) and two external wireless interfaces 202, 204, one of whichis an 802.11a WLAN interface and the other of which is an 802.11b WLANinterface. A similar configuration is shown in FIG. 11, except that acellular WAN interface 206 is provided instead of the 801.11 a interface202 shown in FIG. 10. The configuration of FIG. 12 combines thecapabilities of the configurations of FIG. 10 and FIG. 11 by employingall three types of wireless interfaces; namely, 802.11a, 802.11b and WANinterfaces. Lastly, the configuration of FIG. 13 employs an 802.11binterface and a GPRS interface 208 and a CDMA interface 210. From thenetwork IP address connection (OSI Layer 3) point of view, there arethree IP addresses for the mobile device in the configurations shown inFIG. 10 and FIG. 11 and four IP addresses for the mobile device in theconfigurations shown in FIG. 12 and FIG. 13. In other words, there isone IP address for the LAN interface and a separate IP address for eachof the wireless interfaces.

[0042] For example, assume the configuration shown in FIG. 11 whichcorresponds to the protocol stack shown in FIG. 2. The two externalinterfaces provide gateway routing functions for the internal LAN IPaddress of mobile device 18. Referring to FIG. 14, if the WLAN interface26 is the active interface, data packets from mobile device 18 would becommunicating from LAN interface 22 (IP0) to WLAN 14 through WLANinterface 26 (IP1). On the other hand, if the WAN interface 28 is theactive interface, data packets from mobile device 18 would becommunication from LAN interface 22 (IP0) to WAN 12 through WANinterface 28 (IP2). It will be appreciated, therefore, that the WISE 20protocol stacks shown in FIG. 2 and elsewhere are not limiting; theprotocol stack would be expanded to accommodate any particular numberand/or type of wireless interface to which mobile device 18 would beconnected.

[0043] It will be appreciated, therefore, that WISE 20 provides aseamless roaming capability to a mobile device. However, in addition toseamless roaming, since battery life is an important consideration withany mobile device WISE can provide power management to shut down, or toplace into standby, wireless interfaces that are not being used. Forexample, referring again to FIG. 14, if WLAN interface 26 is not theactive interface, it can be powered down. Note also that, when mobiledevice 18 is moving farther way from, for example, WLAN 14, the signalquality for the WLAN interface 26 may degrade. In that instance, WISE 20can turn on WAN interface 28 in preparation for roaming when the WLANsignal is no longer usable.

[0044] While the invention has been described in terms of specific typesof wireless networks and wireless network interfaces, those skilled inthe art will appreciate the invention is not so limited and that anywireless network and associated network interface can be accommodated.It will further be appreciated that the invention can be implemented infirmware and/or software using conventional hardware design andprogramming techniques. Although the description above contains manydetails, these should not be construed as limiting the scope of theinvention but as merely providing illustrations of some of the presentlypreferred embodiments of this invention. Therefore, it will beappreciated that the scope of the present invention fully encompassesother embodiments which may become obvious to those skilled in the art,and that the scope of the present invention is accordingly to be limitedby nothing other than the appended claims, in which reference to anelement in the singular is not intended to mean “one and only one”unless explicitly so stated, but rather “one or more.” All structural,chemical, and functional equivalents to the elements of theabove-described preferred embodiment that are known to those of ordinaryskill in the art are expressly incorporated herein by reference and areintended to be encompassed by the present claims. Moreover, it is notnecessary for a device or method to address each and every problemsought to be solved by the present invention, for it to be encompassedby the present claims. Furthermore, no element, component, or methodstep in the present disclosure is intended to be dedicated to the publicregardless of whether the element, component, or method step isexplicitly recited in the claims. No claim element herein is to beconstrued under the provisions of 35 U.S.C. 112, sixth paragraph, unlessthe element is expressly recited using the phrase “means for.”

What is claimed is:
 1. A network interface switching apparatus,comprising: a switch engine configured to automatically select acorresponding one of a plurality of wireless network interface devicesassociated with a mobile device while said mobile device roams among aplurality of wireless networks.
 2. An apparatus as recited in claim 1,wherein said switch engine communicates with said mobile device usingTCP/IP protocol.
 3. An apparatus as recited in claim 2, wherein saidswitch engine provides a PPP-less interface with said mobile device. 4.An apparatus as recited in claim 1, wherein said switch enginecommunicates with said wireless interface devices using a Ethernet OSILayer 2 packet header with an IEEE 802.1p tag control information fieldhaving a priority field.
 5. An apparatus as recited in claim 4, whereinthe priority field is used to select a wireless interface based on apriority criteria selected from the group consisting essentially offrame quality, receive frame CRC error, and signal strength.
 6. Anapparatus as recited in claim 1, wherein said switch engine comprises aQoS priority queuing module, a VLAN bandwidth tagging module, a bridgeswitching module, and a switching/packet management table.
 7. A networkinterface switching apparatus, comprising: a switch engine configured asa bridge between a mobile device and a plurality of wireless networkinterface devices associated with said mobile device; wherein as saidmobile device roams among a plurality of wireless networks said switchengine automatically selects a corresponding wireless network device forseamless roaming.
 8. An apparatus as recited in claim 7, wherein saidswitch engine communicates with said mobile device using TCP/IPprotocol.
 9. An apparatus as recited in claim 8, wherein said switchengine provides a PPP-less interface with said mobile device.
 10. Anapparatus as recited in claim 7, wherein said switch engine communicateswith said wireless interface devices using a Ethernet OSI Layer 2 packetheader with an IEEE 802.1p tag control information field having apriority field.
 11. An apparatus as recited in claim 10, wherein thepriority field is used to select a wireless interface based on apriority criteria selected from the group consisting essentially offrame quality, receive frame CRC error, and signal strength.
 12. Anapparatus as recited in claim 7, wherein said switch engine comprises aQoS priority queuing module, a VLAN bandwidth tagging module, a bridgeswitching module, and a switching/packet management table.
 13. A networkinterface switching apparatus, comprising: a switch engine; said switchengine including means for, as a mobile device roams among a pluralityof wireless networks, automatically selecting a corresponding one of aplurality of wireless network interface devices associated with saidmobile device for seamless roaming.
 14. An apparatus as recited in claim13, wherein said switch engine communicates with said mobile deviceusing TCP/IP protocol.
 15. An apparatus as recited in claim 14, whereinsaid switch engine provides a PPP-less interface with said mobiledevice.
 16. An apparatus as recited in claim 13, wherein said switchengine communicates with said wireless interface devices using aEthernet OSI Layer 2 packet header with an IEEE 802.1p tag controlinformation field having a priority field.
 17. An apparatus as recitedin claim 16, wherein the priority field is used to select a wirelessinterface based on a priority criteria selected from the groupconsisting essentially of frame quality, receive frame CRC error, andsignal strength.
 18. An apparatus as recited in claim 13, wherein saidswitch engine comprises a QoS priority queuing module, a VLAN bandwidthtagging module, a bridge switching module, and a switching/packetmanagement table.
 19. A network interface switching apparatus,comprising: a switch engine; said switch engine including means forcommunicating with a mobile device; said switch engine including meansfor communicating with a plurality of wireless network interface devicesassociated with said mobile device; said switch engine including meansfor, as said mobile device roams among a plurality of wireless networks,selecting a corresponding one of said plurality of wireless networkinterface devices for seamless roaming.
 20. An apparatus as recited inclaim 19, wherein said switch engine communicates with said mobiledevice using TCP/IP protocol.
 21. An apparatus as recited in claim 20,wherein said switch engine provides a PPP-less interface with saidmobile device.
 22. An apparatus as recited in claim 19, wherein saidswitch engine communicates with said wireless interface devices using aEthernet OSI Layer 2 packet header with an IEEE 802.1p tag controlinformation field having a priority field.
 23. An apparatus as recitedin claim 22, wherein the priority field is used to select a wirelessinterface based on a priority criteria selected from the groupconsisting essentially of frame quality, receive frame CRC error, andsignal strength.
 24. An apparatus as recited in claim 19, wherein saidswitch engine comprises a QoS priority queuing module, a VLAN bandwidthtagging module, a bridge switching module, and a switching/packetmanagement table.
 25. A network interface switching apparatus,comprising: a switch engine; said switch engine including means forbridging a mobile device and a plurality of wireless network interfacedevices associated with said mobile device; wherein as said mobiledevice roams among a plurality of wireless networks said switch engineautomatically selects a corresponding wireless network device forseamless roaming.
 26. An apparatus as recited in claim 25, wherein saidswitch engine communicates with said mobile device using TCP/IPprotocol.
 27. An apparatus as recited in claim 26, wherein said switchengine provides a PPP-less interface with said mobile device.
 28. Anapparatus as recited in claim 25, wherein said switch enginecommunicates with said wireless interface devices using a Ethernet OSILayer 2 packet header with an IEEE 802.1p tag control information fieldhaving a priority field.
 29. An apparatus as recited in claim 28,wherein the priority field is used to select a wireless interface basedon a priority criteria selected from the group consisting essentially offrame quality, receive frame CRC error, and signal strength.
 30. Anapparatus as recited in claim 25, wherein said switch engine comprises aQoS priority queuing module, a VLAN bandwidth tagging module, a bridgeswitching module, and a switching/packet management table.
 31. A networkinterface switching apparatus, comprising: a switch engine; said switchengine including means for communicating with a mobile device; saidswitch engine including means for communicating with a plurality ofwireless network interface devices associated with said mobile device;said switch engine including means for bridging a mobile device and aplurality of wireless network interface devices associated with saidmobile device; wherein as said mobile device roams among a plurality ofwireless networks said switch engine automatically selects acorresponding wireless network device for seamless roaming.
 32. Anapparatus as recited in claim 31, wherein said switch enginecommunicates with said mobile device using TCP/IP protocol.
 33. Anapparatus as recited in claim 32, wherein said switch engine provides aPPP-less interface with said mobile device.
 34. An apparatus as recitedin claim 31, wherein said switch engine communicates with said wirelessinterface devices using a Ethernet OSI Layer 2 packet header with anIEEE 802.1p tag control information field having a priority field. 35.An apparatus as recited in claim 34, wherein the priority field is usedto select a wireless interface based on a priority criteria selectedfrom the group consisting essentially of frame quality, receive frameCRC error, and signal strength.
 36. An apparatus as recited in claim 31,wherein said switch engine comprises a QoS priority queuing module, aVLAN bandwidth tagging module, a bridge switching module, and aswitching/packet management table.
 37. A multi-network communicationapparatus, comprising: a mobile device; and a switch engine associatedwith said mobile device; said switch engine configured to automaticallyselect a corresponding one of a plurality of wireless network interfacedevices associated with said mobile device while said mobile deviceroams among a plurality of wireless networks.
 38. An apparatus asrecited in claim 37, wherein said switch engine communicates with saidmobile device using TCP/IP protocol.
 39. An apparatus as recited inclaim 38, wherein said switch engine provides a PPP-less interface withsaid mobile device.
 40. An apparatus as recited in claim 37, whereinsaid switch engine communicates with said wireless interface devicesusing a Ethernet OSI Layer 2 packet header with an IEEE 802.1p tagcontrol information field having a priority field.
 41. An apparatus asrecited in claim 40, wherein the priority field is used to select awireless interface based on a priority criteria selected from the groupconsisting essentially of frame quality, receive frame CRC error, andsignal strength.
 42. An apparatus as recited in claim 37, wherein saidswitch engine comprises a QoS priority queuing module, a VLAN bandwidthtagging module, a bridge switching module, and a switching/packetmanagement table.
 43. A multi-network communication apparatus,comprising: a mobile device; a switch engine associated with said mobiledevice; said switch engine configured as a bridge between said mobiledevice and a plurality of wireless network interface devices associatedwith said mobile device; wherein as said mobile device roams among aplurality of wireless networks said switch engine automatically selectsa corresponding wireless network device for seamless roaming.
 44. Anapparatus as recited in claim 43, wherein said switch enginecommunicates with said mobile device using TCP/IP protocol.
 45. Anapparatus as recited in claim 44, wherein said switch engine provides aPPP-less interface with said mobile device.
 46. An apparatus as recitedin claim 43, wherein said switch engine communicates with said wirelessinterface devices using a Ethernet OSI Layer 2 packet header with anIEEE 802.1p tag control information field having a priority field. 47.An apparatus as recited in claim 46, wherein the priority field is usedto select a wireless interface based on a priority criteria selectedfrom the group consisting essentially of frame quality, receive frameCRC error, and signal strength.
 48. An apparatus as recited in claim 43,wherein said switch engine comprises a QoS priority queuing module, aVLAN bandwidth tagging module, a bridge switching module, and aswitching/packet management table.
 49. A multi-network communicationapparatus, comprising: a mobile device; and a switch engine; and saidswitching engine including means for, as said mobile device roams amonga plurality of wireless networks, automatically selecting acorresponding one of a plurality of wireless network interface devicesassociated with said mobile device for seamless roaming.
 50. Anapparatus as recited in claim 49, wherein said switch enginecommunicates with said mobile device using TCP/IP protocol.
 51. Anapparatus as recited in claim 50, wherein said switch engine provides aPPP-less interface with said mobile device.
 52. An apparatus as recitedin claim 49, wherein said switch engine communicates with said wirelessinterface devices using a Ethernet OSI Layer 2 packet header with anIEEE 802.1p tag control information field having a priority field. 53.An apparatus as recited in claim 52, wherein the priority field is usedto select a wireless interface based on a priority criteria selectedfrom the group consisting essentially of frame quality, receive frameCRC error, and signal strength.
 54. An apparatus as recited in claim 49,wherein said switch engine comprises a QoS priority queuing module, aVLAN bandwidth tagging module, a bridge switching module, and aswitching/packet management table.
 55. A multi-network communicationapparatus, comprising: a mobile device; and a switch engine; said switchengine including means for communicating with said mobile device; saidswitch engine including means for communicating with a plurality ofwireless network interface devices associated with said mobile device;said switch engine including means for, as said mobile device roamsamong a plurality of wireless networks, selecting a corresponding one ofsaid plurality of wireless network interface devices for seamlessroaming.
 56. An apparatus as recited in claim 55, wherein said switchengine communicates with said mobile device using TCP/IP protocol. 57.An apparatus as recited in claim 56, wherein said switch engine providesa PPP-less interface with said mobile device.
 58. An apparatus asrecited in claim 55, wherein said switch engine communicates with saidwireless interface devices using a Ethernet OSI Layer 2 packet headerwith an IEEE 802.1p tag control information field having a priorityfield.
 59. An apparatus as recited in claim 58, wherein the priorityfield is used to select a wireless interface based on a prioritycriteria selected from the group consisting essentially of framequality, receive frame CRC error, and signal strength.
 60. An apparatusas recited in claim 55, wherein said switch engine comprises a QoSpriority queuing module, a VLAN bandwidth tagging module, a bridgeswitching module, and a switching/packet management table.
 61. Amulti-network communication apparatus, comprising: a mobile device; anda switch engine; said switch engine including means for bridging saidmobile device and a plurality of wireless network interface devicesassociated with said mobile device; wherein as said mobile device roamsamong a plurality of wireless networks said switch engine automaticallyselects a corresponding wireless network device for seamless roaming.62. An apparatus as recited in claim 61, wherein said switch enginecommunicates with said mobile device using TCP/IP protocol.
 63. Anapparatus as recited in claim 62, wherein said switch engine provides aPPP-less interface with said mobile device.
 64. An apparatus as recitedin claim 61, wherein said switch engine communicates with said wirelessinterface devices using a Ethernet OSI Layer 2 packet header with anIEEE 802.1p tag control information field having a priority field. 65.An apparatus as recited in claim 64, wherein the priority field is usedto select a wireless interface based on a priority criteria selectedfrom the group consisting essentially of frame quality, receive frameCRC error, and signal strength.
 66. An apparatus as recited in claim 61,wherein said switch engine comprises a QoS priority queuing module, aVLAN bandwidth tagging module, a bridge switching module, and aswitching/packet management table.
 67. A multi-network communicationapparatus, comprising: a mobile device; and a switch engine; said switchengine including means for communicating with said mobile device; saidswitch engine including means for communicating with a plurality ofwireless network interface devices associated with said mobile device;said switch engine including means for bridging a mobile device and aplurality of wireless network interface devices associated with saidmobile device; wherein as said mobile device roams among a plurality ofwireless networks said switch engine automatically selects acorresponding wireless network device for seamless roaming.
 68. Anapparatus as recited in claim 67, wherein said switch enginecommunicates with said mobile device using TCP/IP protocol.
 69. Anapparatus as recited in claim 68, wherein said switch engine provides aPPP-less interface with said mobile device.
 70. An apparatus as recitedin claim 67, wherein said switch engine communicates with said wirelessinterface devices using a Ethernet OSI Layer 2 packet header with anIEEE 802.1p tag control information field having a priority field. 71.An apparatus as recited in claim 70, wherein the priority field is usedto select a wireless interface based on a priority criteria selectedfrom the group consisting essentially of frame quality, receive frameCRC error, and signal strength.
 72. An apparatus as recited in claim 67,wherein said switch engine comprises a QoS priority queuing module, aVLAN bandwidth tagging module, a bridge switching module, and aswitching/packet management table.